Precise control of directional migration and spatial organization of multiple cell types is critical to maintaining and engineering tissue function. A major challenge in biomaterials research is the design and fabrication of biomaterials that can guide the simultaneous self-assembly of large number of cells with the precision and efficiency of biological systems. The proposed research builds on the PI and co-PI's recent discovery of MANDIP - Microarray Amplification of Natural Directional Persistence - to guide the long-range directional migration of attached mammalian cells. Key to MANDIP and the natural directional persistence of freely migrating cells is that the envelope of extended lamellipodia is preferentially aligned to the extended cell body. Through an asymmetric arrangement of cell adhesive microarray islands that acts as a ratchet by restricting lamellipodia attachment, MANDIP imposes directionality with overwhelming compliance, guiding simultaneously the migration of unlimited number of cells independently over arbitrary preset paths of unlimited distance without chemoattractants external fields, or mechanical manipulation. The objective of this proposal is to establish a foundation of MANDIP design strategies whose transformative impact will be demonstrated through the following specific aims: Aim 1: Design one-way micropatterns to guide the directional migration of cells on biomaterials, Aim 2: Direct self-assembly of multiple cell types to mimic liver tissue and promote vascularization, Aim 3: Devise a biological analogue of thin-layer chromatography for sorting cells by their intrinsic motility. Accomplishing these aims will bring to fruition MANDIP's potential in promoting tissue pattern formation and as a ubiquitous low-cost cell-sorting platform analogous to thin layer chromatography.